And for all you people obsessed with free flow panel flters, here is an email quote from Mike Wood, in 2005, who was the Technical Director of Prodrive:

''Getting a filter that flows more and has the same filtration standards as the paper one is almost impossible. Whenever we've measured the pressures in the intake system, the filter has only a tiny pressure drop across it, basically only 5mm of mercury or less than 0.01bar which is the smallest unit we can measure accurately measure.

The only way you'll get more power is if changing the filter alters the way that the sensor sees the airflow and it now under reads. Generally this will give more power as the engine will run less rich, but unsafe''.

Note the keyword UNSAFE

 

Both nice to see you back Gregg

Tony

 

So there we have it ..... from the Technical Director of Prodrive ..... the hobbyists argument seems dead in the water!

Sense 1 - 0 Hobbyists

 

Pete, note the words "standard subaru's run rich" adding a little is no problems, having the car mapped for the air filter is no problem
Now if STI produce one for their JDM cars that doesnt blow them up (and they are quite a big part of subaru) is that not also telling you something? (oh and I noticed the difference to the bit of cardboard that didnt let any air through to the paper STI filter btw )

Tony

 

OH, **** ..... I'm using a BluePrint Air Filter instead of the Subaru one ...... and I haven't had it re-mapped

Whatever will I do?

I'll stick to the advice of Technical Top Bod at Prodrive all the same

 

I ain't putting no £4 filter in my car. It's £40 or it aint going in!
Besides, the Subaru ones are expensive anyway but i would still sooner pay more.

 

So not even the people who develope the engines? they dont mind you putting in an air filter Pete they even have one on their books you can use

These are for the latest cars but they do the older ones too
POWER UNIT PARTS[SPORTS PARTS for IMPREZA]

Tony

 

Pete, yet again you have latched onto a bit of information that suits your argument and have ignored any other information posted.

Please have a look at the link I have posted below and the recommendations by one of the most respected and knowledgeable mappers in the UK, this is obviously for owners wishing to uprate their power but Bob does not put his reputation on the line without thoroughly researching.

BRDevelopments

Please note how Bob states that the K&N filter and induction cone plus the RCM induction cone (which I believe that Bob help develop) are MAF friendly.

And to use your winning statement (albeit rehashed for my own purposes) :

So there we have it ..... from Bob Rawle..... the well renowned Subaru king of trollers argument seems dead in the water!

Sense 0 - 1 Hobbyists

 

Well I am surprised if that is the case as I thought that you only fitted genuine Subaru parts to your car Pete, do you have a filtration report on the BluePrint air filter to ensure that it gives the correct level of filtration and what micron size does it filter down to?

Not sure that is entirely up to you as it is your car.

As I will stick to the sage words of Bob Rawle.

 

Well it is funny that you mention Prodrive as the WRC cars I believe used Green cotton air filters and induction cones on their cars, hmm I wonder why that would be?

 

I have only just figured this out
pslewis = SSU.

 

I prefered SSU

TX.

 

I was just about to correct that
Hes an absolute gem

 

They are both entertaining, both sides of the same coin.

He certainly makes coming on Scoobynet worth while.

 

Has he been like this for the whole 10 years of being a scoobynet member??

 

I wouldn't disagree with any of that. As I said at the outset the difference between one filter and another is minimal in terms of outright performance, and as far as the second paragraph is concerned, the alteration of the airflow through the MAF tube is one of the primary knock-on effects of induction kits. There's little way a panel can meaningfully alter the flow past the sensor as the constants are all the same as with the OE setup.

Where I do think there's a more measurable difference between the paper filters and some of the others is in terms of their performance over time. The paper filters deposit muck over the surface of the paper. The reticulated foam/mucus coated types absorb it into the foam where it becomes suspended in the mucus.

The cotton ones absorb some of it into the fibres. I'd be interested in seeing a re-run of Harvey's test performed on filters that are a year or two old. The practical problem in arranging such tests, of course, is that it'd be impossible to put exactly the same usage envelope on them during that time.

A car that is driven hard in dusty conditions will by definition work its filter harder than another that spends most of its time being lightly driven around town with the occasional tickle at the weekend.

Prodrive have used K&N too. If I remember right the standard fit air filter on the S6 and S12b WRC cars was a K&N panel.

While the "it works on a racing car so it must be the dog's on my daily driver" argument doesn't always apply, in this application there's a clear need for efficient air transmission alongside high levels of filtering efficiency. As such the choices the rally team made are quite interesting, within the context of this thread.

 

yes and people still bite

 

Bet you didnt know that Subaru UK use to do Ram-Air Filters for the classics as an accessory (pre phase 2 cars)

Tony